Field of the Invention
The present invention relates to a display device, and more particularly, to a source driver for driving a display panel.
Description of the Related Art
With the development of information technology (IT), the use of display devices have rapidly increased. A display device includes a display panel for displaying an image and a plurality of drivers for driving the display panel. A part of the drivers may include gate drivers to drive scan lines formed in the display panel, and the other part of the drivers may include source drivers to drive data lines formed in the display panel.
In the case of a display panel using an organic light emitting diode (OLED), the source driver includes a plurality of sample and hold (S/H) circuits configured to detect changes in pixel information of a plurality of pixels formed in the display panel.
The sample and hold circuit is provided at each output channel of the source driver so as to detect pixel information. Thus, the source driver includes a plurality of sample and hold circuits corresponding to the number of output channels. A signal outputted from a sample and hold circuit may be converted into a digital signal by an analog-to-digital converter, and then provided to a timing controller.
Furthermore, for a high-speed operation of the analog-to-digital converter, the signal of the sample and hold circuit needs to be amplified and provided. For this operation, an amplification unit is configured to amplify the signal of the sample and hold circuit and provide the amplified signal to the analog-to-digital converter. An offset voltage may be formed at an input terminal of the amplification unit. When the number of sample and hold circuits is increased, a parasitic capacitor may be formed in a transmission line of the amplification unit which receives the output signal of the sample and hold circuit, and parasitic capacitance caused by the parasitic capacitor may be increased.
The increase of the parasitic capacitance may increase the offset voltage generated at the input terminal of the amplification unit. As a result, a difference in offset voltage between the source drivers may occur to thereby reduce the yield of the source drivers.